I had a final payment due date of 28th march for a BA holiday to Madrid. I put in a voucher claim. BA refused to issue a voucher for the deposit saying the non changeable aspect of the booking was more than the deposit. I replied that the hotel is currently closed. BA then ageed to postpone the final payment until 3 weeks before travel. By then it will be clearer whether the FCO no non-essential travel advice will be extended to cover May and Madrid will be still be locked down.